testsuite: Improve check-function-bodies logging

When a check-function-bodies test fails, it can sometimes be hard to
identify which part of a large function regexp is causing the failure.
To aid debugging these failures, find the largest initial set of lines
that matches the function, and log this separately from the remainder of
the regexp.

Additionally, add a newline before logging the function bodies, so that
the first line has the same indentation as the rest of that function.

gcc/testsuite/ChangeLog:

	* lib/scanasm.exp (check_function_body): Log matching portion
	of body_regexp separately.

diff --git a/gcc/testsuite/lib/scanasm.exp b/gcc/testsuite/lib/scanasm.exp
index bcd22c2d7e4ef95c3d918438ffd7c0c2505c74d9..b0df0c6ba28c4dd92494a25a5a896cc40f36fd2a 100644 (file)
--- a/gcc/testsuite/lib/scanasm.exp
+++ b/gcc/testsuite/lib/scanasm.exp
@@ -981,10 +981,38 @@ proc check_function_body { functions name body_regexp } {
     if { ![info exists up_functions($name)] } {
        return 0
     }
-    set fn_res [regexp "^$body_regexp\$" $up_functions($name)]
+    set body $up_functions($name)
+    set fn_res [regexp "^$body_regexp\$" $body]
     if { !$fn_res } {
-      verbose -log "expected: $body_regexp"
-      verbose -log "found: $up_functions($name)"
+      # Find the longest initial set of lines in body_regexp that matches the
+      # function.  We can't just use a binary search here, because adding more
+      # lines to a broken regexp might make it start to match.
+      # Unfortunately this makes runtime quadratic in the number of lines, but
+      # failures in large check-function-body regexps are hopefully rare.
+      set ok_index [string length $body_regexp]
+      incr ok_index -1
+      while { $ok_index >= 0 } {
+       set short_regexp [string range $body_regexp 0 $ok_index]
+       set match_found 0
+       # Not all initial sets of lines are valid.  Ignore any broken regexps.
+       if { ![catch { regexp "^$short_regexp" $body } res] && $res } {
+         break
+       }
+       set ok_index [string last "\n" $body_regexp $ok_index-1]
+      }
+      set head [string range $body_regexp 0 $ok_index]
+      set tail [string range $body_regexp $ok_index+1 end]
+      if { $ok_index == -1 } {
+       verbose -log "no initial matching lines"
+      } else {
+       verbose -log "initial matched regexp:\n$head"
+      }
+      if { [string length $tail] == 0 } {
+       verbose -log "excess lines found after matching regexp\n"
+      } else {
+       verbose -log "mismatch in remaining regexp:\n$tail"
+      }
+      verbose -log "compared against output:\n$body"
     }
     return $fn_res
 }